One of the MLAs targeted in a petrol bomb attack on Alliance party offices has called on all elected representatives to make their condemnation "very clear".

Chris Lyttle was speaking after two petrol bombs were thrown at the property on the Upper Newtownards Road on Saturday night (November 16) – the latest in a series of attacks.

"This attack was carried out in a built up area with a number of local businesses and children's facilities and I can only describe those responsible as incomprehensively reckless," he said.

"Anyone could have been seriously hurt or injured and the police are working hard and giving their full attention to catching those responsible."

Detectives are now calling for witnesses who may have seen a male wearing a red coloured hood top, making off in the direction of Finvoy Street at around 10.45pm, to contact them.

It is the second time this month that the office building shared by MP Naomi Long and MLAs Chris Lyttle and Judith Cochrane has been attacked.

Since the decision to restrict the number of days the Union flag is flown at city hall, the party's office has been the scene of a number of protests and a series of security alerts.

In a joint statement, the First and deputy First Ministers Peter Robinson and Martin McGuinness said the attack struck "at the very heart of democracy and those responsible must stop immediately. These people are intent on bringing fear and disruption to our community. They have nothing to offer our society and will do nothing to deter us from working together across all political parties to achieve a shared future and a united community."

Further condemnation came from East Belfast DUP MLA Robin Newton and SDLP MLA Fearghal McKinney.